S-AWC

DTC C1242: G and Yaw Rate Sensor (Longitudinal G Output Data Error)

CAUTION
^ If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
^ Do not drop the G and yaw rate sensor or subject it to a shock.
^ When G and yaw rate sensor is replaced, calibrate G and yaw rate sensor and initialize the lateral/longitudinal acceleration correction amount stored in AWC-ECU. (Refer to item No.2: Lateral acceleration correction amount initialization, and No.3: Longitudinal acceleration correction amount initialization Special Function Reference Table)

OPERATION
The G and yaw rate sensor outputs the signal to ASC-ECU and AWC-ECU via the special CAN bus lines.

DTC set conditions
This diagnostic trouble code is set when the abnormality below is detected:
^ Abnormality in G and yaw rate sensor output value
^ This diagnostic trouble code is set when AWC-ECU determines that an abnormality is present by comparing the longitudinal G that is output from the G and yaw rate sensor during braking with the calculation value calculated by the data from the wheel speed sensor.

PROBABLE CAUSES
^ Improper installation of G and yaw rate sensor
^ Malfunction of G and yaw rate sensor
^ Malfunction of wheel speed sensor
^ Malfunction of stoplight switch
^ Malfunction of AWC-ECU
^ Malfunction of ASC-ECU

Diagnostic procedure

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.

STEP 2. Check whether the DTC is reset.
Q: Is DTC No. C1242 set?
YES: Go to Step 3.
NO: This diagnosis is complete.

STEP 3. Scan tool diagnostic trouble code
Check the ASC diagnostic trouble code. Diagnostic Trouble Code Descriptions
Q: Is the DTC set?
YES: Perform the relevant troubleshooting.
NO: Go to Step 4.

STEP 4. Scan tool diagnostic trouble code
Q: Is DTC No. C2204 set?
YES: Perform the relevant troubleshooting.
NO: Go to Step 5.

STEP 5. Scan tool diagnostic trouble code
Check if the local CAN communication-related, stoplight switch-related, or wheel speed sensor-related diagnostic trouble code is set.
Q: Is the DTC set?
YES: Perform the relevant troubleshooting.
NO: Go to Step 6.

STEP 6. Check of G and yaw rate sensor installation status
Check that the G and yaw rate sensor is installed correctly.
Q: Is the check result normal?
YES: Go to Step 7.
NO: Reinstall the G and yaw rate sensor correctly. Then go to Step 7.

STEP 7. Scan tool service data
Item No. 31: Longitudinal G sensor (Data List Reference Table)
Q: Is the check result normal?
YES: Go to Step 8.
NO: Replace the G and yaw rate sensor. Then go to Step 8.

STEP 8. Check whether the DTC is reset.
Q: Is DTC No. C1242 set?
YES: Replace the AWC-ECU. Then go to Step 9.
NO: Intermittent malfunction.

STEP 9. Check whether the DTC is reset.
Q: Is DTC No. C1242 set?
YES: Return to Step 1.
NO: This diagnosis is complete.